This invention in general concerns a tube bender, and more particularly concerns a tube bending apparatus especially adapted for efficiently forming structural supports for use in fabricating a utility building, such as a greenhouse.
The present application is based on subject matter disclosed in confidence to the U.S. Patent and Trademark Office through the Disclosure Document Program thereof. The subject disclosure was deposited on Jan. 27, 1987 and assigned Disclosure Document No. 162707.
Various devices for bending tubes or similar items are generally known, and have long been in use. Some are provided with relatively fixed configurations for performance of specific tasks while others include interchangeable parts for permitting the selection of curvature characteristics to be induced into a subject pipe tube, or wire.
As examples of some prior art devices, Lidseen (U.S. Pat No. 1,899,280) discloses a generally vertical structure having a curved shoe which is controllably moved upward by a fluid pressure cylinder for bending tubes captured between such shoe and bending rollers. The bending shoe does not extend the full width between the bending rollers, and is not guided in parallel upright guide channels. Allen (U.S. Pat. No. 3,344,635) and Goldberg (U.S. Pat. No. 4,005,593) disclose similar type bending devices, having reduced sized bending shoes. Opposed triangular-shaped plates of Allen partially guide its respective bending shoe so long as the shoe is adjacent its retracted position. Harvey (U.S. Pat. No. 1,775,762) and Gregg (U.S. Pat. No. 3,512,392) disclose various tube benders having bending shoes which extend substantially between opposing capture members, but none of which are guided in parallel, vertical guide channels. Huth (U.S. Pat. No. 3,429,157) and Shaw, Sr. et al. (U.S. Pat. No. 4,558,583) both disclose tube benders having interchangeable bending shoes of different sizes for achieving different selected curvatures in the resulting bent tube.